3, - 6,9, - 12 , - 2004, 2007, 2010, complete the following questions: (1) Write the 100th number in this column (2) Find the sum of this column

3, - 6,9, - 12 , - 2004, 2007, 2010, complete the following questions: (1) Write the 100th number in this column (2) Find the sum of this column

(1) The 100th number: - 300
（2）3-6+9-12+.-2004+2007-2010
=-3-3-3 -. - 3-3 (335-3)
=--1005

Mr. Wang's house is to be decorated with a 9-meter-long and 5-meter-wide house. It is planned to lay bricks on the ground. There are three kinds of floor tiles: (1) side length is 30 cm; (2) side length
50 cm: (3) side length 60 cm
Please help Mr. Wang choose a kind of floor tile that does not cost materials, and calculate how many floor tiles to use at least

If it's a mathematical problem, then choose 50 cm. Because 50 cm, regardless of vertical and horizontal, can take the whole number. A total of 180 tiles
And 30 cm and 90 cm, in the width of 5 meters under this condition, are not integer
Of course, if it is in real life, which pattern is good-looking, choose which one. Because you can divide a floor tile into several rectangles to stick to the wall

Aunt Chen plans to pave the floor tiles for her daughter's room. It is known that the room is 4.5 meters long, 3 meters wide and 8 meters wide. If you buy a floor tile with a side length of 50 cm, how much faster do you need to buy?

Length 4.5m = 450cm
450 △ 50 = 9 pieces
Width 3M = 300cm
300 △ 50 = 6 pieces
Need to buy floor tiles 9x6 = 54

）The structure of a house is shown in the figure. The owner of the house plans to lay floor tiles on the parts outside the bedroom. How many square meters of floor tiles do he need at least? If the price of a certain floor tile is a yuan / m2, how many yuan do he need to buy the floor tiles?
(2) It is known that the height of the house is h meters. Now it is necessary to paste wallpaper on the walls of the living room and bedroom. How many square meters of wallpaper do you need? If the price of some kind of wallpaper is B yuan / m2, how many yuan do you need to buy the required wallpaper? (the area occupied by doors and windows is not deducted in the calculation)

(1) The area of living room + kitchen + toilet = 2x * 4Y + X * (4y-2y) + y * (4x-x-2x) = 8xy + 2XY + xy = (11xy) square meters answer: at least (11xy) square meters of floor tiles are needed. Floor area * unit price of floor tiles = 11xy * a = (11axy) yuan answer: at least (11axy) yuan is needed to buy floor tiles